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30 December 2018

The Evolution of Home Heating in America

In this day and age, tending to one of our most beloved creature comforts, home heating, is as simple as bumping the thermostat up or down a degree or two. But hey, it’s not always been quite so easy! Home heating has come a long way and we’re about to take a look at it.

The Fireplace

In early-1700s America, most homes were heated with a simple, but VERY inefficient fireplace. Fireplaces were the common means of heating homes in England. They weren’t really that good there and were even worse for settlers in the colder American colonies. You see, the fireplace heated the home by radiant heat. The problem was that most of the heat from the wood went straight up the chimney, around 90%. This would only leave 10% to be radiated outward from the fireplace opening to heat the home. Now, factor in that a typical fireplace could easily suck 400 cubic feet of air per minute up the chimney (which is about half of a small room's air), and that 400 cfm would have to be pulled back into the house through cracks and crevices from the cold outside environment, and you had a heating source that offered only one or two percent efficiency... that's pretty bad!

Rumford Fireplace

Several "great minds" of the day saw the opportunity to improve on this wood-consuming beast and were, for the most part, unsuccessful. Ol’ Ben Franklin was one of them. Sir Benjamin Thompson, also known as Count Rumford, would improve the design of the fireplace by introducing a narrower, shallow firebox in the back, a wider opening in front and angled side walls to reflect more heat out into the room. The Rumford fireplace was a welcomed success and is still a popular design to this day!

The Wood Stove & Coal Stove

Another home heating method used during the 1700s was the iron stove. The design for the stove originated in Germany nearly 200 years before it was popularized and mass-produced in the United States. The wood-burning stove was more efficient than the fireplace as heat could radiate outward on all four sides as well as the top and bottom of this cast iron beauty. Even the stove pipe gave up some heat before sending the toxic gasses, smoke, to the outside. Yes, wood was the primary fuel source at the beginning of the 19th century, but by the 1820s and 30s, a new resource was coming into play: coal.

While coal was being regularly imported from Europe to coastal cities in the U.S. around the 1820s, only commercial buildings or wealthy homeowners would have been able to afford it, due to its increased transport price. It took a bit of "selling" the idea of coal as fuel in the beginning. It was billed as "the fuel of the fashionable" and was promised to "revolutionize home heating." After all, one could load up the coal stove firebox before bedtime and still have hot embers glowing at dawn. Not the case with wood, as folks waking to wood stoves would often complain of their feet sticking to the frozen floor as they sprang out of bed.

By the 1840s, improved transportation routes opened up U.S. coal mining for wider distribution to family homes. Stoves that could burn both wood and coal were produced, but coal became the primary fuel source for heating America's homes from the mid-1800s through the early-1900s. Even though the coal stove's popularity dwindled nationally, the Appalachian region still continued heating their homes this way well into the 20th century, due to the availability of cheap residential stove-grade coal.

Coal Marches On and Enables Central Heating

Now up to this point, our poor predecessors have only had single-point heating, meaning, if you were close to the fireplace or stove, you were warm. If not...brrr! It was a Russian invention of the 1850s that would alleviate this infirmity and would become the precursor of modern central heating systems: the radiator. This apparatus was a heat exchanger designed for heating a designated space through a centralized system of piping and radiators. A coal-fired boiler in the basement would be used to heat water, creating steam which traveled upward through pipes and into cast-iron radiators, heating EVERY room where a radiator was located...sweet!

Well, it wasn’t perfect, though. Pipes tend to rust and spring leaks and there is always that little issue of the boiler creating too much steam and, yes, exploding. Eventually, the central air furnace came along, which used natural convection as its heating mechanism. The warm air created by the coal-fired furnace would rise, traveling from the basement through ducts (rectangular-shaped metal channels) into the rooms above. And no skin-scorching radiators for junior to bump into and get burned.

Thermostat

The thermostat was a small, but significant game-changer in the world of comfort heating. We often take this small device for granted without considering how it improved daily quality of life. Coming into play around 1885, the thermostat allowed automatic temperature control of the furnace. Prior to this, homeowners were accustomed to filling up the firebox with coal at night, then waking early in the morning to add in new coal. Then the waiting game began, as the heating system's response was not instantaneous. Through trial and error, those who regularly did the stoking grew familiar with how much coal to use, but the process was still not perfect. If they added too little, the fire would go out in the night. If they added too much, this precious commodity was simply wasted. The first electric coal stoker with a thermostat control became available in 1912 and an abundance of automatic coal systems were being manufactured by the 1920s.

Forced Air Furnace Propels Heating Forward

The warm-air furnace was upgraded by the addition of the electric fan or blower, which significantly increased heat circulation. The first forced air furnaces, which were fueled by coal, became widely available to homeowners around 1935.

As shown on the chart, 1940 would be a strong year for coal, which was used to heat over half, of all households at the time. However, coal would slowly be replaced by more efficient and less laborious oil and natural gas.

The oil furnace was introduced in 1920 and became popular over the next few decades. Not having to continually stoke the coal fire was an attractive feature of oil and gas furnaces. By 1950, the new fuels were gaining ground, with about 25% using gas or oil to heat their homes.

Straight Electric Heat

Coming into play soon after the introduction of electricity, straight electric heat is simply what the name implies: heat produced from electric resistance heating, or heating elements. The heat produced from heating elements can be distributed by a) radiation such as inset wall, electric coil bathroom heaters, b) convection as with standard baseboard heaters or c) circulated by central, forced-air electric furnace systems found in most manufactured homes produced in the last half of the 20th century. However, as seen in the graph above, electric heat has never been the primary heating preference in the U.S. due to its high utility cost, it is often the preferred back-up or emergency heat for other, more efficient systems such as our next and last topic… the heat pump.

The Heat Pump

Around 1945, Robert C. Webber, an employee of the Indianapolis Power and Light Company, discovered that he could make good use of the heat removed from his deep freezer by heating his water with it. He then started experimenting with heat acquisition from external sources such as the warm outside ground via the refrigeration process, which had up to this point, been mostly focused on heat removal. As the technology advanced, more and more heat pumps came to use the outside air as the heat source. The reversing valve also allowed the heat pump to transfer heat into or out of the home depending on the season.

Although the heat pump is powered by electricity, the selling point is that it produces 3 to 4 times more energy than the electrical energy that it consumes. Heat pumps offer big payoffs in areas with moderate climates, such as the southeast, but it is not as popular in the cold northern climates, as it becomes very difficult to extract heat from outside air below 20°F. With each passing year however, the heat pump becomes more efficient and therefore, more popular across the U.S. To learn more about air source heat pumps, see “How Does a Heat Pump Work?”{link}

The Conclusion

In summary, we have come from having to labor in the woods cutting trees, splitting the wood and then tending to the fireplace almost constantly, to spending five minutes changing return air filters once every month or so. Albeit and aesthetically speaking, the ambiance of the fireplace is unrivaled to date, this author is thankful for the advancements leading to modern home heating.